Recent Precipitation Trends in Hungary in the Context of Larger Scale Climatic Changes   总被引：1，自引：0，他引：1  

Domonkos  Peter 《Natural Hazards》2003,29(2):255-271

The time series of monthly precipitation totals from 14 Hungarian observing stations (1901–1998) were analysed to reveal the long term changes in precipitation characteristics occurred in the 20th century. A particular attention was given to the changes in the recent decades and their links with the larger scale climatic and circulation changes over Europe and the Atlantic.The statistical significancesof systematic changes are controlled by linear trend analysis and the Mann–Kendall test. The long term fluctuations are illustrated applying a 15-point Gaussian filter on the time series. The Standardised Precipitation Index is used to evaluate the changes in the drought event frequency. The relationships with larger scale changes are mostly discussed relying on contemporary papers, and the Grosswetterlagen Catalogue is used as well.The annual precipitation total decreased by 15–20% in Hungary during the 20th century. The decline is substantial in both halves of the century, but the precipitation sums in the transition seasons declined in the first 50 years, and the winter precipitation decreased in the latest decades. The precipitation total of the period November–February declined significantly in the last 50 years. In the same time the mean winter value of the North Atlantic Oscillation Index (NAOI) increased, the positions of the main pressure patterns over the Atlantic are shifted northeastward, and lot of other coherent changes detected in the winter climate of the European–Atlantic region. The mean summer precipitation total has hardly changed, but the frequency of summer drought events increased. There are some signs of a shift of the Hungarian summer climate towards a Mediterranean like climate.  相似文献   

基桩有效桩长几个问题的探讨   总被引：5，自引：1，他引：5  

曾友金  章为民  王年香  徐光明 《岩土力学》2003,(Z2)

从离心模型试验成果、超长单桩静载试验成果、工程实践及其他学者研究成果中,论证了普通单桩存在有效桩长。深入解释了有效桩长的含义,指出了与临界桩长概念有区别。在分析目前有效桩长定义基础上,提出了合理的有效桩长定义。明确了研究普通单桩有效桩长的意义及存在的问题,并提出了在一定条件下,合理确定有效桩长就是合理设计桩长。  相似文献   

脑卒中与气象要素关系的探讨   总被引：10，自引：4，他引：10       下载免费PDF全文

陆晨 《气象科技》2003,31(6):397-399

1994年1月至2000年12月北京地区若干社区脑卒中发病人数与同期气象资料分析结果表明：北京地区脑卒中发病有明显的季节性，冬春季高发，夏秋季低发；出血性脑卒中发病是春秋季高发，夏季低发；缺血性脑卒中发病是夏季高，秋季低。脑卒中发病与气温、气压和相对湿度有密切关系；寒冷与高温，气温、气压的剧烈变化等，可能是诱发脑卒中的重要气象因素。  相似文献   

荒漠戈壁下垫面表面动量和感热湍流通量参数化研究   总被引：9，自引：0，他引：9  

ZHANG Qiang  HUANG Ronghui  TIAN Hui 《大气科学进展》2003,20(1):111-118

用合理筛选以后的野外观测资料，研究了荒漠戈壁地表湍流通量参数化的问题。首先，分析了Monin-obukhov相似函数的特征，并拟台出了其经验公式。结果表明，风速和温度相似性函数随稳定度参数的变化曲线与典型经验曲线差异较小，并且在经验曲线分布范围以内，但中性时的值有所不同。同时，还用该资料给出了动量和标量粗糙度(感热粗糙度)长度的平均值及其标量粗糙度随摩擦速度的变化关系。发现标量粗糙度的平均值大约比动量粗糙度的小一个量级，并且随摩擦速度的增大而减小，但明显比其理论预测值要大。  相似文献   

用Voronoi方法为MapInfo扩展拓扑功能     

陈军  崔秉良 《武汉大学学报(信息科学版)》1997,(3)

分析了Ｖｏｒｏｎｏｉ图在表达邻近关系方面的特性，提出了用Ｖｏｒｏｎｏｉ方法为ＭａｐＩｎｆｏ建立动态邻近关系并扩展拓扑功能的方法。  相似文献   

临安地区强酸雨的特点   总被引：3，自引：0，他引：3       下载免费PDF全文

洪盛茂 《大气科学》1997,21(1):31-38

本文对1985年至1994年监测的强酸雨资料进行研究和分析，并与一般酸雨进行对比。结果表明，本地的一般酸雨出现较为频繁；强酸雨出现增多；四季中强酸雨频率各不相同，秋季最高，夏季最低；强酸雨的酸沉降量正在逐年增加；强酸雨的电导率较高，电导率和pH间呈现高度显著的负相关；强酸雨的降水量一般较小，并与pH间显现非常显著的正相关；强酸雨中各离子浓度均高于一般酸雨。  相似文献   

地磁1年周期变化的响应函数     

陈伯舫 《地震地磁观测与研究》1997,18(2):40-44

用通日月均值减去夜均值计算的月均值资料和Ｓｏｍｐｉ谱分析法分析了１４个台站的北向分量１年周期变化的振幅向相位，时段为１９８４－１９８８年。分析结果显示用Ｐ＾０ｎ（ｄｎｄ＝１，…，６）复合模式的估算的Ｃ值较合理。各台的Ｃ值比较一致。  相似文献   

人地非线性相关作用的探讨   总被引：12，自引：2，他引：12  

刘继生  陈涛 《地理科学》1997,17(3):224-230

从自组织系统思想出发，提出了人地关系的基本特性，通过逻辑斯蒂听数学变换，分析了人地非线性相关作用的混沌特性，进而讨论了人地关系的分形性质。基于混 过程与分形结构的因果关系，指出：地球表层系统中的人文分形景观乃是人地非线性关系的混沌作用所致。  相似文献   

RILL EROSION PROCESS ON STEEP SLOPE LAND OF THE LOESS PLATEAU     

ZHENG Fenli  TANG Keli 《国际泥沙研究》1997,(1)

IntheLoessPlateau,alongtheslopelengthfromthetoptothebottom,soilerosionischaracterizedbyobviousverticalzonaldivision,thatis,sheeterosionzone,sheeterosionandrillerosionzone,rillerosionandshallowgullyerosionzoneandgullyerosionzone.Inthesheetandrillero..sionzone,rillerosionamounttakesup70%ofthetotalsoilloss[TANGKenetal.,1983,ZHENGFenlietal.,19871;intherillandshallowgullyerosionzone,rillerosionamountaccountsfor30--40%ofthetotalsoilloss.Sorillerosionisamajorerosionpatternonsteepslopeland.Riller…  相似文献   

Assessment of hydrogeological conditions in basement aquifers of the Precambrian Oban massif, southeastern Nigeria   总被引：1，自引：0，他引：1  

A.E. Edet  C.S. Okereke 《Journal of Applied Geophysics》1997,36(4):195-204

A combined analysis of lineament length density from radar imagery and surface resistivity data is used to assess the hydrogeological conditions in the Oban massif, Nigeria. The results show that the data guided the qualitative and quantitative estimation of some aquifer parameters. These include resistivity of the water bearing formations (280–740 ω m), thickness (5–140 m), limited hydraulic conductivity (8.53-13.18 m/day) and transmissivity (410.65–725.88 m²/day) data. In addition, the lineament length density for the area ranged between less than 0.2 to slightly more than 0.4. Site evaluation for the location of productive boreholes/wells using a groundwater potential index (GWPI) indicates that areas with a GWPI of greater than 35 are consistent with relatively high yield.  相似文献